gms | German Medical Science

Objective: The need for using multiple trajectories and intraoperative testing in an awake patient during DBS for Parkinson’s disease is discussed controversially. In our department it was done in all cases. We aimed to find out if there is a benefit for such a procedure in the clinical outcome.

Methods: We retrospectively analysed all data of patients, who have undergone DBS-surgery for Parkinson’s disease in our department in 2012 and 2014. We recorded the number of microelectrodes, the trajectory of the permanent electrode, the reasons for avoiding the central trajectory and the clinical outcome (UPDRS Part III). The intraoperative effect was defined as the improvement of the rigor estimated in % by a neurologist. The clinical outcome was measured as the difference between the preoperative UPDRS III under L-dopa medication and the postoperative UPDRS III under L-Dopa medication and stimulation. Possible influencing factors on the clinical outcome were estimated with a linear regression model (p<0,05).

Results: In the study period 67 patients were treated with bilateral DBS of the STN because of Parkinson’s disease (134 implantations of permanent electrodes). In 88,4% of the 134 implantations 3 or more trajectories were used for microrecording and intraoperative testing. For implantation of the permanent electrode, the central trajectory was used in 58%. In the remaining patients (42%), we used the anterior trajectory in 56%, in 25,7% the medial and in 18,3% the lateral trajectory. The reason for not using the central trajectory was a better intraoperative effect in 65,4%. Changing the trajectory due to a better intraoperative effect was found to be an independent, significant (p= 0,001) predictor for the clinical outcome with the coefficient factor 8,32 on the right and 9,93 on the left side.

Conclusion: Using multiple trajectories leads to a deviation from the central trajectory in 42% of the implantations, predominantly due to a better intraoperative effect. This intraoperative testing has turned out to be significantly positively correlated with the clinical outcome (even after controlling for the other variables). This result is in line with the hypothesis that deviating from the central trajectory due to intraoperative testing leads to a better clinical outcome. However, a matched pair analysis between the operation with awake and intubated patients, which would allow the test for a causal relationship, has not been done yet but belongs to our agenda.

Figure 1 [Fig. 1], Table 1 [Tab. 1]